The present invention relates generally to an electrical connector member and, more specifically, to a zero insertion force socket or connector for integrated circuits. .
U.S. Pat. No. Re. 28,171 to Anhalt discloses a zero insertion force electrical connector in which, when the plug and receptacle connector members are initially mated, the contacts therein are spaced from each other. An actuating plate is shifted to move the movable contacts in the plug connector member in tandem in a direction to engage the fixed contacts in the receptacle connector member. U.S. Pat. No. 4,397,512 to Barraire et al. discloses a zero insertion force connector or socket for an integrated circuit of the type having rows two of leads on the opposite sides of the carrier. The leads are inserted into the socket with zero insertion force, and an actuating plate is shifted laterally to bring the contacts of the socket into engagement with the leads, similar to the arrangement disclosed in the aforementioned Anhalt patent. In each of the aforementioned prior art connector and socket the actuator plate is formed of nonconductive material and therefore provides no electrical shielding function.
Recently very large scale integrated circuits have become available which are mounted in carriers having a high number of pins or leads extending downwardly therefrom in a rectangular array, with the pins located within an extremely dense matrix, for example, with pin spacing being about 0.070". In one such carrier, there are 1,089 leads arranged in 33 rows to provide a square matrix. Thus, the matrix of leads is 2.240" long on each side. With such a large number of leads, it will be appreciated that the leads must be inserted into a socket with zero insertion force to avoid the risk of damage to the leads, and to the integrated circuit within the carrier. Also it is desirable to provide electrical shielding for the leads to prevent signal loss and/or signal distortion. This requires that the walls separating the contacts in the socket be formed of conductive material, preferably metal.
Due to the very high density contact requirement for a socket to be utilized with the integrated circuit carrier of the type described above, the forming of very small contact cavities in the socket, which are very close to each other, by conventional machining techniques, would be cost prohibitive. Thin wall sections within the socket and small diameter-to-length ratios of the contact cavities would cause extremely low part yield. Casting and molding technology cannot hold the close tolerances necessary to meet the design requirements for high pin count and high pin density integrated circuit sockets.
It is the object of the present invention to provide an integrated circuit socket having conductive walls forming contact cavities having very small cross section, located in a very dense pattern, yet will prevent contact shorting, which is economical to manufacture and will allow connection with the leads of an integrated circuit carrier with zero insertion force.